Aircraft having computers distributed in the fuselage

ABSTRACT

An aircraft comprising a fuselage ( 1 ) subdivided by a floor ( 2 ) into a top volume ( 3 ) and a bottom value ( 4 ) in which girders ( 5 ) extend supporting the floor and co-operating with the fuselage and the floor to define two lateral housings ( 6 ) that are of substantially triangular cross-section and that extend parallel to a longitudinal axis of the fuselage. Calculation units ( 100 ) are arranged in the lateral housings and each comprises a box ( 101 ) defining a main compartment containing calculation modules ( 122 ) insertable into the main compartment along an insertion axis through an opening in the compartment and connectable to the connectors ( 115 ) carried by a back wall ( 116 ) of the compartment so as to extend into the main compartment opposite from the opening, the insertion axis being substantially parallel to the longitudinal axis of the fuselage.

The present invention relates to the field of aviation.

STATE OF THE ART

An aircraft for transporting passengers generally comprises a fuselagethat is subdivided by a floor into a top volume constituting a cabincontaining seats for receiving passengers, and a bottom volumecomprising a hold for receiving passenger baggage. Girders extend in thebottom volume supporting the floor and co-operating with the fuselageand the floor to define two lateral housings (commonly referred to as“cargo triangle zones”) that are of substantially triangularcross-section and that extend parallel to the longitudinal axis of thefuselage on either side of a middle zone (commonly referred to as the“useful cargo zone”). Because of their shape, the lateral housings areconsidered as dead volume that is used solely for passing various cablesand fluid ducts used in the operation of the aircraft and of itsequipment.

It is known to install calculation units or bays in the middle zone ofthe bottom volume, generally in the vicinity of the aircraft cockpit,each of which units or bays comprises a housing defining a compartmentcontaining calculation modules that can be inserted into the compartmentalong an insertion axis through an opening of the compartment and thatare connectable to connectors carried by a back wall of the compartmentand extending into the compartment opposite from its opening. The term“calculation module” is used herein to cover any electronic circuitcapable of processing signals and/or data, and in particular capable ofperforming calculations on those signals or data. The electronic circuitmay form a computer and may comprise a set of processors of theapplication-specific integrated circuit (ASIC) type or of some othertype, a programmable array such as a field programmable gate array(FPGA) . . . . The calculation modules are connected mainly to thecontrol instruments on which the pilot of the aircraft acts, toindicators for providing the pilot with information, to sensorsdistributed throughout the aircraft, and to pieces of equipment of theaircraft.

The desire to optimize the occupation of space within the aircraft makesinstalling calculation units on board an aircraft problematic.

OBJECT OF THE INVENTION

An object of the invention is to provide a solution to that problem.

BRIEF SUMMARY OF THE INVENTION

To this end, the invention provides an aircraft comprising a fuselageand calculation units distributed in the fuselage. The fuselage issubdivided by a floor into a top volume and a bottom value in whichgirders extend supporting the floor and co-operating with the fuselageand the floor to define two lateral housings that are of substantiallytriangular cross-section and that extend parallel to a longitudinal axisof the fuselage. The calculation units are arranged in the bottomvolume, and each comprises a box defining a main compartment containingcalculation modules insertable into the main compartment along aninsertion axis through an opening in the compartment and connectable toconnectors carried by a back wall of the main compartment so as toextend into the main compartment opposite from the opening. Thecalculation units are arranged in at least one of the lateral housingsin such a manner that the insertion axis is substantially parallel tothe longitudinal axis of the fuselage.

Thus, the invention makes it possible to use the lateral housings of thebottom volume by housing the calculation units therein, withoutexcessively impeding accessibility to the calculation modules and theconnectors enabling the calculation modules to be connected to theelectrical harness of the aircraft.

According to a first particular characteristic, the box defines anauxiliary compartment for a common cooling module connected to a coolingair duct.

The common module then preferably includes a check valve arranged toallow cooling air to pass from the duct towards the common module and tooppose any flow of air in the opposite direction, and the common moduleincludes an external air intake associated with a fan for introducingair into the common module and with a check valve arranged to allow airto pass from the fan towards the common module and to oppose any flow ofair in the opposite direction.

Advantageously, the common module includes an external air intake and afan that is mounted facing the air intake and that is associated with adevice for filtering air by centrifuging.

According to a second particular characteristic, one of the electronicmodules is arranged along two mutually opposite directions of aninsertion axis for insertion into the compartment, the compartmenthaving electrical power supply means for powering the electronic moduleand connection means of the electronic unit for connection to theelectronic module, these means extending onto a connection face formingpart of the reception compartment and extending parallel to theinsertion axis.

According to a third particular characteristic, at least one of thecalculation modules includes pins for engaging in metal-plated holes ofa printed circuit board, the printed circuit board being covered in alayer of electrically insulating flexible material that is pierced bythe pins when they are engaged in the metal-plated holes and that isclamped between a support for the pins and the printed circuit board.

Other characteristics and advantages of the invention appear on readingthe following description of particular, non-limiting embodiments of theinvention.

BRIEF DESCRIPTION OF THE FIGURES

Reference is made to the accompanying drawings, in which:

FIG. 1 is a diagrammatic view of an aircraft of the invention;

FIG. 2 is a diagrammatic view of the aircraft in section on line II ofFIG. 1;

FIG. 3 is a diagrammatic side view of a calculation unit of theinvention;

FIG. 4 is an enlarged diagrammatic view in section on plane II of FIG. 1showing the common cooling and power supply module;

FIG. 5 is a diagrammatic front view of a fan in this common cooling andpower supply module;

FIG. 6 is a cross-section view showing one of the calculation modulesbeing connected to a printed circuit plate;

FIG. 7 is a fragmentary perspective view of a compartment of acalculation unit and of a first type of electronic module for mountingtherein;

FIG. 8 is a schematic of an electronic circuit of a first type for anelectronic module of the invention;

FIG. 9 is a diagrammatic perspective view of a second type of electronicmodule of the invention;

FIG. 10 is a view identical to FIG. 1 showing the electronic modulesbefore they are installed in the calculation unit;

FIG. 11 is a detail view in section on plane XI-XI of FIG. 7, showing astep of mounting an electronic module in a calculation unit of theinvention;

FIG. 12 is a detail view in section on plane XI-XI of an electronicmodule mounted in a calculation unit of the invention;

FIG. 13 is a diagrammatic view of a connection face of a particularembodiment of a calculation unit of the invention;

FIG. 14 is a view in longitudinal section on plane XIV-XIV of FIG. 13,showing the calculation unit;

FIG. 15 is a diagrammatic view of a connection face of a common modulein a particular embodiment of the invention;

FIG. 16 is a view in section on plane XIV-XIV showing the FIG. 14calculation unit assembled with the FIG. 15 common module;

FIG. 17 is a view similar to the view of FIG. 16, showing a first stepof removing the common module;

FIG. 18 is a view similar to the view of FIG. 16 showing a second stepof removing the common module; and

FIG. 19 is a view similar to the view of FIG. 16, showing a third stepof removing the common module.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the figures, the aircraft generally comprises afuselage 1 subdivided by a floor 2 into a top volume 3 and a bottomvolume 4. The top volume 3 is for receiving seats for passengers and itconstitutes the cabin of the aircraft; the bottom volume 4 is forreceiving passenger baggage or freight and it constitutes the hold ofthe aircraft.

Girders 5 extend in the bottom volume 4 to support the floor 2 and theycooperate with the fuselage 1 and the floor 2 to define lateral housings6 of cross-section that is substantially triangular and that extendparallel to a longitudinal axis L of the fuselage 1 on either side of amiddle or central zone 7. In the lateral housings 6 under the floor 2there extend cables 8 of the electrical harness 9 of the aircraft andone of the main air conditioning pipes or tubes 10 conveying air that isblown into the top volume 3 for air conditioning purposes. Theelectrical harness 9 is made up of cables used for transmitting powerand cables for transmitting control signals and data.

The aircraft has calculation units 100, each comprising a box 101defining a main compartment 102, a first auxiliary compartment 103extending under the main compartment 102, and a second auxiliarycompartment 104 extending behind a top portion of the first auxiliarycompartment 102 and behind a bottom portion of the main compartment 102.The box 101 has a front opening 105 giving access to the maincompartment 102; two lateral openings 106 giving access to the maincompartment 102; two lateral openings 107, opposite from each other,giving access to the first auxiliary compartment 103; and two lateralopenings 108, opposite from each other, giving access to the secondauxiliary compartment 104. The front opening 105 is left open; thelateral openings 106 are closed by a removable panel 109; the lateralopenings 107, 108 facing towards the middle zone 7 are left open; thelateral openings 107, 108 facing away from the middle zone 7 are closedby a removable panel 110, 111. The removable panels are held in theclosed position by a quick-connection mechanism or by screws. The panels110, 111 may be mounted on one or the other of the lateral openings 107,108 depending on the direction in which the calculation unit 100 ismounted in the lateral housings 6, as described below.

The main compartment 102 contains calculation modules, given overallreference 122; the first auxiliary compartment 103 contains a commonmodule, given overall reference 123, for cooling and powering thecalculation modules 122; and the second auxiliary compartment 104contains a common module, given overall reference 124, forinterconnecting the calculation modules 122. The common modules 123, 124provide a transverse function for the calculation modules 122.

The calculation modules 122 can be inserted into the main compartment102 along an insertion axis I through the front opening 105 of the box101 and they are connectable to connectors 115 carried by a back wall116 of the box 101 so as to extend into the main compartment 102remotely from the front opening 105. Each calculation module 122 has anoutwardly projecting front face which is fastened to the box 101 andwhich closes the opening 105 in part (this opening being completelyclosed when all of the calculation modules 122 are in place). Theconnectors 115 are connected to cables of the electrical harness 9intended mainly for transmitting control signals and data so as toconnect the calculation modules 122 mainly to the control instruments onwhich the pilot of the aircraft acts, to indicators for providing thepilot with information, to sensors distributed within the aircraft, andto the equipment of the aircraft.

Advantageously, the back wall 116 has means for quickly fasteningconnectors 115 on the box 101, specifically notches 190 receivingresilient tabs 191 carried by the connectors 115. The connectors 115,when fastened in this way on the box 101, contribute to positioning andmechanically holding the modules 122, and they serve to minimize theeffects of static redundancy between the modules 122 and the box 101.The connectors 115 are arranged so as to be directly connected on themodules 122 (i.e. each connector 115 co-operates with a connector thatis carried directly by a module). The box 101 thus does not have theusual “backplane blocks” serving to provide specific electronicinterconnections between the connectors 115 carried by the cables of theelectricity network 9 and the modules 122. Thus, the specificconnections between a module 122 and the electrical harness 9 arecarried exclusively by a connector 115 and the functions that are commonto all of the modules 122 (interconnection, electrical power supply,tooling, . . . ) are provided by using the common modules 123 and 124.This particular aspect of the invention contributes to reducing thenumber of different part numbers that need to be stored for maintenanceand repair operations, and also serves to reduce the cost of fabricatinga calculation unit 100, since the box 101 no longer requires a specificbackplane block for providing interconnections between the connector 115and the module 122.

The particular configuration of the calculation units 100 gives easyaccess to the back walls 116 of the boxes 101, thereby guaranteeingrapid action when connecting or disconnecting modules 122 relative tothe electrical harness 9 or during installation or for maintenanceoperations.

The calculation modules 122 comprise a printed circuit board carryingelectronic control and/or power components: they are themselves knownand are not described in greater detail herein. The calculation modules122 also carry respective connectors on their edges remote from theopening 105 enabling them to be connected to connectors carried by aface of a printed circuit board 118 between the bottom portion of theback of the main compartment 102 and the second auxiliary compartment104, and extending into the first auxiliary compartment 103. Thecalculation modules 122 are mounted in the main compartment 102 viaslideways 117 that are fastened in the box 1 in order to extendperpendicularly to the opening 105 and thus parallel to the insertionaxis I. The slideways 117 are made of thermally conductive material soas to conduct away a portion of the heat produced by the electroniccomponents of the calculation modules 122 to the box 101. For thispurpose, the box 101 is made at least in part out of thermallyconductive material so as to enable the heat produced by the operationof the calculation modules 122 to be discharged to the outside. Inaddition, the box has openings in its top wall to allow a convective airstream to escape.

The connectors of the calculation modules 122 enabling them to beconnected to the printed circuit board 118 include a projecting support150 from which pins 151 extend parallel to the insertion axis I, whichpins 151 are elastically deformable in a plane extending transversely totheir longitudinal axes, between a relaxed state and a deformed state,the pins 151 presenting a cross-section in the relaxed state that isgreater than in the deformed state. The corresponding connector of theprinted circuit board 118 has metal-plated holes 152, each serving toreceive a respective pin 151, which is engaged by force in themetal-plated hole and is held clamped therein in its deformed state. Theprinted circuit board 118 is not placed in an enclosure that isdust-proof. In an airplane having a fuselage made of carbon, there is arisk of carbon dust becoming deposited on the printed circuit plate, andof that giving rise to short circuits. To avoid that, the printedcircuit board 118 is covered in a layer of electrically insulatingmaterial 153 that is pierced by the pins 151 when they are engaged inthe metal-plated holes 152. When the calculation modules 122 areconnected to the printed circuit board 118, the layer of electricallyinsulating material 153 is clamped between the supports 150 and theprinted circuit board 118, thereby tending to close any tears that mightbe made by the pins 151, and thus preventing dust from penetratingbetween the calculation modules 122 and the printed circuit board 118.In this example, the electrically insulating material is a silicone, andmore particularly a silicone that is suitable for room temperaturevulcanization (RTV). Naturally, any material presenting elastomericbehavior could be used, and in particular silicones of other types.

The common module 123 is inserted in the first auxiliary compartment 103via the lateral opening 107 facing towards the middle zone 7 along aninsertion axis P that is perpendicular to the insertion axis I. Thecommon module 123 has an overlapping front face 112 that is fastened tothe box 101 and that cuts the opening 107.

As can be seen in FIGS. 7 and 10, the common module 124 is inserted inthe second auxiliary compartment 104 via the lateral opening 108 facingtowards the middle zone 7 along an insertion axis P′ perpendicular tothe insertion axis I. The common module 124 has an outwardly-projectingfront face that is fastened to the box 101 and that shuts the opening108.

Both of the common modules 123 and 124 carry flexible contacts enablingthem to be connected to conductive areas of the printed circuit board118, which is itself connected firstly to the calculation modules 122 asmentioned above, and secondly to a connector 119 carried by the backwall 116 and connected to power cables and control cables of theelectrical harness 9.

The flexible contacts are arranged on either side of a middle lineparallel to the insertion axis so that the contacts for receiving powercomprise a positive pole and a negative pole extending along a lineperpendicular to the middle line, with one of the poles above the middleline and the other pole below the middle line.

The second auxiliary compartment 104 has a connection face 160 extendingparallel to the insertion axis P′, and facing the printed circuit 118. Afirst conductive area 161 and a second conductive area 162 arranged oneither side of a middle line 163 of the connection face 160 extend ontothe connection face 160. A central conductive area 164 situated on themiddle line 163 also extends onto the connection face 160. Theconductive areas 161, 162, and 164 are oblong and extend along an axisparallel to the middle line 163. The first conductive area 161 isconnected to a first track of the printed circuit 118 and constitutes apositive pole of an electrical power supply 165, the second conductivearea 162 is connected to a second track of the printed circuit 118 andconstitutes a negative pole of an electrical power supply 165. Thecentral conductive area 164 constitutes a ground of the electrical powersupply 165. Magnetic couplers 166.1 to 166.12 also extend onto theconnection face 160. A first series of magnetic couplers comprises themagnetic couplers 166.1 to 166.6, which extend symmetrically on eitherside of the middle line 163 close to a first opening 108 of thecompartment 104. A second series of magnetic couplers comprises themagnetic couplers 166.7 to 166.12, which extend symmetrically on eitherside of the middle line 163 in the proximity of a second opening 108 ofthe compartment 104, remote from the first opening 108. Optical couplers167.1 to 167.4 also extend onto the connection face 160. A first seriesof optical couplers comprises the optical couplers 167.1 and 167.2,which extend symmetrically on either side of the middle line 163 in theproximity of a first opening 108 of the compartment 104. A second seriesof optical couplers comprises the optical couplers 167.3 and 167.4,which extend symmetrically on either side of the middle line 163 in theproximity of a second opening 108 of the compartment 104 remote from thefirst opening 108. The first series of optical couplers 167.1 and 167.2,and the first series of magnetic couplers 166.1 to 166.6 are symmetricalrespectively with the second series of optical couplers 167.3 and 167.4and with the second series of magnetic couplers 166.7 to 166.12 about amidplane of the face 160 that extends orthogonally to the middle axis163.

The magnetic couplers 166.1 to 166.12 and the optical couplers 167.1 to167.4 are connected to the printed circuit 118. The connection face 160is covered in a fine layer 168 of polytetrafluoroethyelene (PTFE) andthe face 169 opposite from the connection face 160 has threelongitudinal springs 170.1 to 170.3 extending parallel to the middleline 163. The printed circuit 118 is connected firstly to thecalculation modules 122, as mentioned above, and secondly to a connector119 carried by the back wall 116 and connected to power cables andcontrol cables of the electrical harness 9.

In this example, the module 124 is of substantially rectangular boxshape and comprises two insertion ends given respective references 125and 126 of the module 124 leading into the compartment 104 along twoopposite directions along the insertion axis P′. The module 124 also hasa connection face 127 for connection to the box 100 onto which thereextend first and second flexible contacts respectively 171 and 172 thatare arranged on either side of a middle line 173 of the connection face127. A central third flexible contact 174 situated on the middle line173 also extends onto the connection face 127. As can be seen in FIG. 7,the flexible contacts 171, 172, and 174 extend along an axis parallel tothe middle line 173 and the connection face 127 extends parallel to theinsertion axis P′. Magnetic couplers 175.1 to 175.12 also extend ontothe connection face 127. A first series of magnetic couplers comprisesthe magnetic couplers 175.1 to 175.6, which extend symmetrically oneither side of the middle line 173 in the proximity of the insertion end125. A second series of magnetic couplers comprises the magneticcouplers 175.7 to 175.12, which extend symmetrically on either side ofthe middle line 173 in the proximity of the insertion end 126. Opticalcouplers 176.1 to 176.4 also extend onto the connection face 127 andextend symmetrically on either side of the middle line 173. A firstseries of optical couplers comprises optical couplers 176.1 and 176.2,which extend symmetrically on either side of the middle line 173 in theproximity of the insertion end 125. A second series of optical couplerscomprises the optical couplers 176.3 and 176.4, which extendsymmetrically on either side of the middle line 173 in the proximity ofthe insertion end 126. The first series of optical couplers 176.1 and176.2 and the first series of magnetic couplers 175.1 to 175.6 aresymmetrical respectively to the second series of optical couplers 176.3and 176.4 and to the second series of magnetic couplers 175.7 to 175.12about a midplane of the face 127 orthogonal to the middle axis 173. Theconnection face 127 is covered in a fine layer 177 of PTFE.

The flexible contacts 171 and 172, the magnetic couplers 175.1 to175.12, and the optical couplers 176.1 to 176.4 are connected to anelectronic circuit 180, which comprises a first circuit 181 and a secondcircuit 182. For reasons of clarity, only two magnetic couplers 175.1and 175.4 of the set of magnetic couplers 175.1 to 175.6 and of opticalcouplers 176.1 and 176.2 are shown in the schematic of FIG. 8. Theflexible contacts 171 and 172 are connected to the input terminals of afirst circuit 181, which comprises a diode bridge 183. The first circuit181 serves to deliver a constant power supply polarity between itsoutput terminals 184 and 185 regardless of the polarity of the voltageapplied between the flexible contacts 171 and 172. The second circuit183 is connected to the magnetic couplers 175.1 and 175.4 which, in thisexample, are emitter/receivers in which the emission portion goes to lowimpedance as a function of the polarity of the voltage applied betweenthe flexible contacts 171 and 172. This low impedance is provided by ametal oxide on silicon (MOS) transistor 186 having its gate subjected tothe voltage applied between the flexible contacts 171 and 172. A zenerdiode 187 protects the input of the MOS transistor 186 from voltagesurges. Thus, the second circuit 183 serves to modify the direction ofcommunication of the couplers 175.1 and 175.4 as a function of thepolarity of the voltage applied between the flexible contacts 171 and172. With the second circuit 183 connected in the same manner to theother magnetic and optical couplers, it serves likewise to modify thedirection of communication of the magnetic couplers 175.1 to 175.12 andof the optical couplers 176.1 to 176.4 as a function of the polarity ofthe voltage applied between the flexible contacts 171 and 172.

The module 123 also has a connection face 527 for connection to the box100 and onto which there extend a first flexible contact 571 and asecond flexible contact 572 that are arranged on either side of a middleline 573 of the connection face 527. A central third flexible contact574 situated on the middle line 573 also extends onto the connectionface 527. As can be seen in FIG. 9, the flexible contacts 571, 572, and574 extend along an axis parallel to the middle line 573 and theconnection face 527 extends parallel to the insertion axis P. Theconnection face 527 may include ventilation connectors (not shown)connected to the fan 140 of the module 123 and electrical connectors formonitoring operation.

With reference to FIG. 10, there follows a description of installingfour identical common modules 124, 224, 324, 424 respectively in fourcalculation units 100, 200, 300, and 400 of a fuselage 1 of an aircraft.Elements that are identical or analogous to those of the common module124 are given numerical references respectively increased by onehundred, two hundred, and three hundred, respectively for designatingelements of the common modules 224, 324, and 424. Elements that areidentical or analogous to those of the calculation unit 100 havenumerical references that are increased respectively by one hundred, bytwo hundred, and by three hundred, for designating respective elementsof the calculation units 200, 300, and 400.

The calculation units 100 and 200 are situated respectively on the rightand on the left of a longitudinal axis L of the fuselage 1, and theyhave their respective front openings 105 and 205 opening towards thefront of the fuselage 1. The calculation units 300 and 400 are situatedrespectively on the right and the left of a longitudinal axis L of thefuselage 1, and they have their respective front openings 305 and 405opening towards the rear of the fuselage 1.

The common module 124 is mounted in the compartment 104 of the unit 100by inserting the insertion end 126 of the common module 124 into thelateral opening 108 facing towards the middle zone 7 of the compartment104 along an insertion axis P′ perpendicular to the longitudinal axis L,the connection face 127 facing towards the front of the fuselage 1.While the common module 123 is moving in translation in the compartment104, the PTFE layers 168 and 177 on the respective connection faces 160and 127 come into contact under the effect of the longitudinal springs170.1 to 170.3 and they slide one against the other. As can be seen inFIG. 11, the flexible contacts 171, 172, and 174 are pushed back by theconnection face 160 as they enter into the second auxiliary compartment104 and they slide against the PTFE layer 168 of the connection face 160until they come respectively face to face with the conductive areas 161,162, and 164. In this position, the optical couplers 176.1 to 176.4 andthe magnetic couplers 175.1 to 175.12 of the connection face 127 of thecommon module 124 face respectively the optical couplers 167.1 to 167.4and the magnetic couplers 166.1 to 166.12 of the connection face 160 ofthe second auxiliary compartment 104. The layers 168 and 177 alsoguarantee a controlled distance between the connection faces 160 and127. The positive pole of the electrical power supply 165 of the secondauxiliary compartment 104 as constituted by the first conductive area161 is electrically in contact with the flexible contact 171 of thecommon module 124. The negative pole of the electrical power supply 165of the second auxiliary compartment 104 as constituted by the secondconductive area 162 is electrically in contact with the flexible contact172 of the common module 124. Thus, the first circuit 181 receives avoltage U₁₇₁₋₁₇₂ measured between the first and second flexible contacts171 and 172, which voltage is positive. The second circuit 182 then goespast the magnetic couplers 175.1 to 175.3 and 175.7 to 175.9 and alsothe optical couplers 176.1 to 176.3 in “emission” mode, and it goes pastthe magnetic couplers 175.4 to 175.6, 175.9 to 175.12, and the opticalcouplers 176.2 and 176.4 in “reception” mode. The common module 124 isremoved from the second auxiliary compartment 104 by taking hold of theend 125 of the common module 124 in order to cause it to move intranslation along the axis P. During this movement in translation, theflexible contacts 171, 172, and 174 are pushed back by the connectionface 160 and they slide against the PTFE layer 168 of the connectionface 160 until the common module 124 is completely extracted from thesecond auxiliary compartment 104.

The common module 224 is mounted in the compartment 204 of the unit 200by inserting the insertion end 225 of the common module 224 into thelateral opening 208 facing towards the middle zone 7 of the secondauxiliary compartment 204 along an insertion axis P′ perpendicular tothe longitudinal axis L, the connection face 227 facing towards thefront of the fuselage 1. In this position, the optical couplers 276.1 to276.4 and the magnetic couplers 276.1 to 276.12 of the connection face227 of the common module 224 face respectively the optical couplers267.1 to 267.4 and the magnetic couplers 266.1 to 266.12 of theconnection face 260 of the second auxiliary compartment 204. Thepositive pole of the electrical power supply 265 of the second auxiliarycompartment 204 as constituted by the first conductive area 261 is inelectrical contact with the flexible contacts 271 of the common module224. The negative pole of the electrical power supply 265 of the secondauxiliary compartment 204, as constituted by the second conductive area262 is electrically in contact with the flexible contact 272 of thecommon module 224. Thus, the first circuit 281 receives a voltageU₂₇₁₋₂₇₂, measured between the first and second flexible contacts 271and 272, which voltage is positive. The second circuit 282 then goespast the magnetic couplers 275.1 to 275.3 and 275.7 to 257.9 and alsothe optical couplers 276.1 and 276.3 in “emission” mode, and goes pastthe magnetic couplers 275.4 to 275.6, 275.10 to 275.12, and the opticalcouplers 276.2 and 276.4 in “reception” mode.

The common module 324 is mounted in the compartment 304 of the unit 300by inserting the insertion end 326 of the common module 324 in thelateral opening 308 facing towards the middle zone 7 of the secondauxiliary compartment 304 along an insertion axis P′ perpendicular tothe longitudinal axis L, the connection face 327 facing towards the rearof the fuselage 1. In this position, the optical couplers 376.1, 376.2,376.3, 376.4 and also the magnetic couplers 375.1 to 375.6 and 375.7 to375.12 of the connection face 327 of the common module 324 facerespectively the optical couplers 367.4, 367.3, 367.2, and 367.1 and themagnetic couplers 366.12 to 366.7 and 366.6 to 366.1 of the connectionface 360 of the second auxiliary compartment 304. The positive pole ofthe electrical power supply 365 of the second auxiliary compartment 304as constituted by the first conductive area 361 is electrically incontact with the flexible contact 372 of the common module 324. Thenegative pole of the electrical power supply 365 of the second auxiliarycompartment 304 as constituted by the second conductive area 362 iselectrically in contact with the flexible contact 372 of the commonmodule 324. Thus, the first circuit 381 receives a voltage U₃₇₁₋₃₇₂, asmeasured between the first and second flexible contacts 371 and 372,which voltage is negative. The second circuit 382 then goes past themagnetic couplers 375.1 to 375.3 and 375.7 to 357.9, and the opticalcouplers 376.1 and 376.3 in “reception” mode, and goes past the magneticcouplers 375.4 to 375.6, 375.10 to 375.12, and the optical couplers376.2 and 376.4 in “emission” mode.

The common module 424 is mounted in the compartment 404 of the unit 400by inserting the insertion end 425 of the common module 424 in thelateral opening 408 facing towards the middle zone 7 of the secondauxiliary compartment 404 along an insertion axis P′ perpendicular tothe longitudinal axis L, the connection face 427 facing towards the rearof the fuselage 1. In this position, the optical couplers 476.1, 476.2,476.3, 476.4 and also the magnetic couplers 475.1 to 475.6 and 475.7 to475.12 of the connection face 427 of the common module 424 facerespectively the optical couplers 467.4, 467.3, 467.2, and 467.1 and themagnetic couplers 466.12 to 466.7 and 466.6 to 466.1 of the connectionface 460 of the second auxiliary compartment 404. The positive pole ofthe electrical power supply 465 of the second auxiliary compartment 404as constituted by the second conductive area 461 is electrically incontact with the flexible contact 472 of the common module 424. Thenegative pole of the electrical power supply 465 of the second auxiliarycompartment 404, as constituted by the second conductive area 462 iselectrically in contact with the flexible contact 472 of the commonmodule 424. Thus, the first circuit 481 receives a voltage U₄₇₁₋₄₇₂,measured between the first and second flexible contacts 471 and 472,which voltage is negative. The second circuit 482 then goes past themagnetic couplers 475.1, 475.2, 475.3, and the optical coupler 476.1 in“reception” mode, and goes past the magnetic couplers 475.4, 475.5,475.6, and 476.2 in “emission” mode.

It can be understood that the above-described arrangement of theflexible contacts makes it possible to use identical common modules 124,224, 324, 424 in the calculation units 100, 200, 300, and 400, since itsuffices to turn the common module about its longitudinal axis so thatthe electrical contacts lie either on the left or else on the right.

This results in having a single model for the calculation unit thatco-operates with a single type of module and that can be mounted in fourdifferent configurations without modification. The costs involved incertification, production, maintenance, and installation are thusgreatly reduced.

Elements that are identical or analogous to those of the calculationunit 100 are given numerical references increased respectively by fourhundred in the description below of a particular embodiment of acalculation unit of the invention.

With reference to FIG. 13, the connection face 560 of the secondauxiliary housing 504 has five conductive tracks 561, 562, 564, 590, and591. The first conductive area 561 is connected to a first track of theprinted circuit 518 and constitutes a positive pole of an electricalpower supply 565, the second conductive area 562 is connected to asecond track of the printed circuit 518 and constitutes a negative poleof an electrical power supply 565. The central conductive track 564constitutes a ground of the electrical power supply 565. The additionaltracks 590 and 591 that extend symmetrically on either side of themiddle line 563 are respectively input ports and output ports forcommunication. Magnetic couplers 592.1 to 592.5 also extend onto theconnection face 560. These magnetic couplers extend symmetrically oneither side of the middle line 563 in the proximity of a first opening508 of the compartment 504.

As can be seen in FIG. 14, the printed circuit 518 has a metal plate 593extending over the entire connection surface 560 and having fastenedthereto the conductive areas 561, 562, 564, 590, and 591 and also thewindings of the magnetic couplers 592.1 to 592.5. The PTFE layer 568covers the plate 593 and includes respective gaps in register with theconductive areas 561, 562, 564, 590, 591. The printed circuit 518 alsohas shielding cylinders 594.1 to 594.5 for shielding the magneticcouplers 592.1 to 592.5 and extending in the proximity of the plate 593remote from the layer 568.

As can be seen in FIGS. 15 and 16, the connection face 527 of the commonmodule 524 also has a metal plate 594 extending over the entireconnection surface 560 and having fastened thereto the flexible contacts571, 572, 574, 595, and 596 and also windings of the magnetic couplers597.1 to 597.5. The flexible contacts 571, 572, 574, 595, and 596respectively comprise three resilient bridges 571.1 to 571.3, 572.1 to572.3, 574.1 to 574.3, 595.1 to 595.3, and 596.1 to 596.3. The PTFElayer 577 covers the plate 594 and includes respective gaps in registerwith the conductive areas 571, 572, 574, 595, 596. The connection face560 also has shielding cylinders 598.1 to 594.5 for shielding themagnetic couplers 592.1 to 592.5 and extending in the proximity of theface of the plate 593 opposite from the layer 568.

When the common module 524 is in place in the second auxiliary housing504 (FIG. 16), the magnetic couplers 597.1 to 597.5 of the common module524 face the magnetic couplers 592.1 to 592.5 of the calculation unit500, thereby providing magnetic coupling between the unit 500 and themodule 524. The resilient bridges of the flexible contacts 571, 572,574, 595, and 596 come respectively into contact with the conductiveareas 561, 562, 564, 590, and 591, thereby powering the common module524 from the power supply 565 and putting the common module 524 intocommunication with the calculation unit 500. The facing metal plates 593and 594 provide effective capacitive coupling between the common module524 and the calculation unit 500.

The common module 524 is removed from the second auxiliary compartment504 by taking hold of the end 525 of the common module 524 so as tocause it to move in translation along the axis P. During this movementin translation, the bridges of the flexible contacts 571, 572, and 574are pushed back by the connection face 560 and they slide against thePTFE layer 568 of the connection face 560 until the common module 524 iscompletely extracted from the second auxiliary compartment 104 (FIGS. 17to 19).

The calculation units 100 are arranged in at least one of the lateralhousings 6 so that the insertion axis I is substantially parallel to thelongitudinal axis L of the fuselage 1. It should be observed thatremoving the panel 109 gives access directly to the calculation module122 that is closest to the middle zone 7.

More precisely, the calculation units 100 are mounted in pairs inadjacent positions in the lateral housings 6 so that the back walls 116of the boxes 101 extend facing each other. Cables 8 of the electricalharness 9 are taken between the two calculation units 100 in order to beconnected thereto via the connectors 115 and 119, thereby facilitatingconnecting the calculation units 100 to the electrical harness 9.

It can be understood that the above-described arrangement of theflexible contacts makes it possible to use identical common modules 123and 124 in both calculation units 100 since it suffices to turn thecommon module about its longitudinal axis and the insertion axis for theelectrical contacts to be located either on the left or else on theright.

The common module 123 is described in detail below. A duct 11 extendingbetween the fuselage 1 and the calculation unit 100 serves to connectthe main pipe 10 closest to an air intake mounted on the panel 110 so asto open out facing an opening in the common module 113 having a firstcheck valve 130.1 arranged facing it so as to allow cooling air to passfrom the duct 11 to the common module 123 while opposing any flow of airin the opposite direction. The common module 123 has an external airintake 120 that opens out into the central zone 7 and that is associatedwith a fan 140 for injecting air into the common module 123 and with asecond check valve 130.2 that is arranged to allow air to pass from thefan 140 to the common module 123 while opposing any flow of air in theopposite direction. The common module 123 has a top wall provided withair discharge openings leading to the main compartment 102.

The check valves 130.1 and 130.2 are similar to each other and in thisexample each of them comprises a hollow body 131 fastened to one of thelateral walls of the common module 123 and connected in sealed manner tothe duct 11 for the valve 130.1, or to the outlet from the fan 140 forthe valve 130.2. The body 131 has a plurality of openings, each having aflap 132 facing it with an edge on one side that is free and on theopposite side, an edge that is hinged to the body 131 so that the flap132 can pivot between a closed position and an open position. The flaps132 are thus positioned in such a manner that they can be lifted by astream of air going towards the inside of the common module 123 so as toallow the stream of air to pass, but they are pressed down into a closedposition by any stream of air in the opposite direction. By way ofexample, the return means may comprise a spring rated to allow the flaps132 to be lifted by a stream of air entering into the common module 123without giving rise to a loss of head in the stream of air that wouldprevent it from traveling along the common module 123 and the maincompartment 102. In a variant, the return means could be provided bygravity. It can be understood that:

-   -   when the air-blowing system of the aircraft is in operation, the        check valve 130.1 allows air to pass and the fan 140 is stopped,        when the check valve 130.2 prevents the passage of air coming        from the check valve 130.1; and    -   when the air-blowing system of the aircraft has failed, the fan        140 is put into operation to blow air so that the check valve        130.2 allows air to pass, while the check valve 130.1 prevents        the passage of air coming from the check valve 130.2. The fan        140 is put into operation under control delivered via the        electrical harness 9 after detecting a failure of the        air-blowing system of the aircraft.

The fan 140 in this example comprises an impeller wheel 141 driven by anelectric motor (not shown) to rotate inside a casing 142. The casing 142has two walls 143 perpendicular to the axis of rotation of the impellerwheel 141, which walls are connected together by a circular peripheralwall 144 surrounding the impeller wheel 141 and extending between thewalls 143. One of the walls 143 is fastened to the wall of the commonmodule 123 and the other one of the walls 143 is provided with airexhaust orifices 145 in the vicinity of the circular peripheral wall144, while being spaced apart from the circular peripheral wall 144. Thecircular peripheral wall 144 extends around the impeller wheel 141 andhas a bottom portion that is extended tangentially by a verticaltangential passage 146 having a container 147 fastened thereto. Theimpeller wheel 141 has a hollow hub forming a duct in communication withthe air intake 120 so that rotation of the impeller wheel 141 tends toentrain air coming from the air intake 120 and going towards theorifices 145 in the casing 142. Any dust that might be found in the airstream is entrained by the centrifugal effect against the circularperipheral wall 144 and then into the vertical tangential passage 146and the container 147, where the dust is trapped. Cleaning the container147 serves to remove the dust.

Naturally, the invention is not limited to the embodiments described butcovers any variant coming within the ambit of the invention as definedby the claims. In particular, the housing of the calculation unit 100may be of some other shape and may have some other number of auxiliarycompartments, and need not have any auxiliary compartment at all.

Although the presently-described module is a module that is common tothe calculation modules, the invention applies equally well to othertypes of electronic module, e.g. such as fan modules or modulesdedicated to only some of the calculation modules or to only one ofthem.

Although in this example the electronic module is powered using oblongconductive areas, the invention applies equally well to other means forelectrically powering the electronic module, such as for exampleconductive areas that are circular or inductive connectors withoutcontact.

Although in this example the connection faces of the electronic moduleand of the second auxiliary compartment have a coating of PTFE, theinvention applies equally well to other types of coating that reducefriction, such as coatings of polychlorotrifluoroethylene (PCTFE),fluoroethylene (FE), methylfluoroalkoxy (MFA), or other polymers. Theinvention also applies to a single connection face—of the electronicmodule or of the calculation unit—that is provided with a coating forreducing friction. The coating may extend over the entire connectionface or over only a portion of the face.

Although in this example the second auxiliary compartment has threelongitudinal springs, the invention applies equally well to other typesof resilient element arranged to exert a force to establish contactagainst the connection face, such as for example a single longitudinalspring, rubber blades, or spiral springs.

Although in this example the common module is substantially ofrectangular box shape, the invention applies equally well to modules ofsome other shape, such as for example right cylindrical or triangularmodules.

Although in this example, the electronic module has flexible contacts,the invention applies equally well to other means for connecting to anelectrical power supply, such as for example stationary electricalconnection studs, inductive connectors that do not make contact, orconductive brushes.

Although in this example, the electronic module, like the calculationunit, has optical couplers and magnetic couplers, the invention appliesequally well to other connection means, such as for example conductiveareas or radio or microwave transceivers. Magnetic and/or opticalconnections are preferred since they provide electrical decouplingbetween the electronic module and the calculation unit.

Although in this example the connection means are distributedsymmetrically about a middle axis and a plane orthogonal to that axis,the invention applies equally well to connection means distributed insome other way, it then being necessary likewise to be able to reversethe common module about an axis perpendicular to its insertion axis.Under such particular circumstances, the common module is inserted intothe compartment always via the same insertion end. Although in thisexample the unit is a calculation unit, the invention applies equallywell to other types of electronic unit, such as for example acommunications unit, an air conditioning unit, etc.

Although in this example the back wall of the box has notches receivingresilient tabs carried by the connectors, the invention applies equallyto other means for fastening the connectors quickly onto the box, suchas for example bayonet couplings, magnetic couplings, resilient plugs,pins.

In a variant, the common module is arranged to provide a singletransverse function, for example supplying electrical power to thecalculation modules, cooling the calculation modules, or providinginterconnections between the calculation modules.

In a variant, it is possible to use common modules that are for use inone position only, either having flexible contacts on the right orflexible contacts on the left. In another variant, the common moduleshave a back provided with a connector and the box of the calculationunit may be fitted with a complementary connector that is movable so asto be mounted on the backplanes of the auxiliary compartments,regardless of the direction in which the calculation unit is mounted inthe lateral housing.

In a variant, other ventilation means could be used, for example a fanarranged behind a filter serving to prevent dust being injected into thecommon cooling module.

The invention claimed is:
 1. An aircraft comprising a fuselage andcalculation units distributed in the fuselage, the fuselage beingsubdivided by a floor into a top volume and a bottom volume in whichgirders extend supporting the floor and co-operating with the fuselageand the floor to define two lateral housings that are of substantiallytriangular cross-section and that extend parallel to a longitudinal axisof the fuselage, the calculation units being arranged in the bottomvolume and each comprising a box defining a main compartment containingcalculation modules insertable into the main compartment along aninsertion axis through a first opening in the compartment andconnectable to connectors carried by the cables of an electricitynetwork of the aircraft so as to extend into the main compartmentopposite from the first opening, the calculation units being arranged inat least one of the lateral housings in such a manner that the insertionaxis is substantially parallel to the longitudinal axis of the fuselage.2. The aircraft according to claim 1, wherein the box includes quickfastener means for fastening the connectors to the box, the connectorsbeing arranged to be connected directly to the modules.
 3. The aircraftaccording to claim 1, including an air conditioning circuit for airconditioning the top volume, the air conditioning circuit including anair-blowing tube that extends under the floor in the lateral housings ofthe bottom volume and that is connected to a common cooling module forcooling the calculation modules of each calculation unit, the commoncooling module being arranged under the calculation means and incommunication with the main compartment, and the box including an airdischarge vent extending into the main compartment above the calculationmodules.
 4. The aircraft according to claim 3, wherein the commoncooling module is connected to the tube by a duct extending between thefuselage and the calculation unit.
 5. The aircraft according to claim 3,wherein the common module includes a check valve arranged to allowcooling air to pass from the duct towards the common module and tooppose any flow of air in the opposite direction, and the common moduleincludes an external air intake associated with a fan for introducingair into the common module and with a check valve arranged to allow airto pass from the fan towards the common module and to oppose any flow ofair in the opposite direction.
 6. The aircraft according to claim 3,wherein the common module includes an external air intake and a fan thatis mounted facing the air intake and that is associated with a devicefor filtering air by centrifuging.
 7. The aircraft according to claim 6,wherein the fan comprises an impeller wheel driven by an electric motorto rotate in a casing, a circular peripheral wall extended tangentiallyby a vertical tangential passage having a bottom end with adust-recovery container fastened thereto, the casing including an airinlet orifice in the vicinity of the axis of rotation of the impellerand at least one air outlet orifice in the vicinity of the circularperipheral wall.
 8. The aircraft according to claim 1, wherein the boxof the calculation units defines an auxiliary compartment receiving acommon module that performs a transverse function for the calculationmodules and that is inserted into the auxiliary compartment via anopening along an insertion axis perpendicular to the longitudinal axisof the fuselage in such a manner that the opening of the auxiliarycompartment faces towards a middle zone of the bottom volume.
 9. Theaircraft according to claim 8, wherein the common module is arranged topower the calculation modules.
 10. The aircraft according to claim 8,wherein the common module is arranged to transmit data with thecalculation modules.
 11. The aircraft according to claim 8, wherein thecommon module is arranged to cool the calculation modules.
 12. Theaircraft according to claim 8, wherein at least one connector extendsonto a side of the auxiliary compartment adjacent to the opening of theauxiliary compartment in order to cooperate with a lateral connector ofthe common module and provide an electrical connection during insertionof the common module into the auxiliary compartment.
 13. The aircraftaccording to claim 1, comprising two calculation units mounted inadjacent positions in a common lateral housing, the back walls of theboxes extending facing each other.
 14. The aircraft according to claim1, wherein the box possesses a second opening giving access to the maincompartment, the second opening being made in a side of the boxperpendicular to the first opening.
 15. The aircraft according to claim1, wherein one of the electronic modules is arranged along two mutuallyopposite directions of an insertion axis for insertion into thecompartment, the compartment having electrical power supply means forpowering the electronic module and connection means of the electronicunit for connection to the electronic module, these means extending ontoa connection face forming part of the reception compartment andextending parallel to the insertion axis.
 16. The aircraft according toclaim 15, wherein the power supply means comprise a first conductivearea and a second conductive area arranged on opposite sides of a middleline of the connection face, one of the first and second conductiveareas being the positive pole of the electrical power supply of theelectronic module, the other one of the first and second conductiveareas being the negative pole of the electrical power supply of theelectronic module.
 17. The aircraft according to claim 16, wherein theconductive areas extend along respective axes parallel to the middleline.
 18. The aircraft according to claim 15, wherein the connectionface is coated at least in part by a friction-reducing coating.
 19. Theaircraft according to claim 15, wherein the connection means forconnecting the electronic module to the electronic unit comprise atleast one magnetic coupler.
 20. The aircraft according to claim 15,wherein the connection means for connecting the electronic module to theelectronic unit comprise at least one optical coupler.
 21. The aircraftaccording to claim 15, wherein a face of the compartment opposite fromthe connection face includes at least one resilient element arranged toexert a contact-making force against the connection face.
 22. Theaircraft according to claim 1, wherein at least one of the calculationmodules includes pins for engaging in metal-plated holes of a printedcircuit board the printed circuit board being covered in a layer ofelectrically insulating flexible material that is pierced by the pinswhen they are engaged in the metal-plated holes and that is clampedbetween a support for the pins and the printed circuit board.
 23. Theaircraft according to claim 1, wherein the electrically insulatingmaterial is a silicone, and more particularly a silicone for roomtemperature vulcanization.
 24. The aircraft according to claim 2,wherein the quick fastener means for fastening the connectors on the boxcomprise notches and/or resilient tabs.